Effect of Hydrocarbon Chain and Amide Linkage on the Interfacial and Self-Assembly Properties of Nicotinic Acid Amphiphiles

Abstract

Three nicotinic acid amphiphiles, sodium 6-octylnicotinate (SONA), sodium 6-decylnicotinate (SDNA), and sodium 6-decylnicotinic glycinate (SDNAG), have been synthesized, and the effect of hydrocarbon chain length as well as amide linkage on the self-assembly properties in aqueous solutions have been investigated using a number of techniques, including tensiometry, fluorometry, FT-IR spectroscopy, 1H NMR spectroscopy, UV–vis spectroscopy, dynamic light scattering, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Tensiometry measurements reveal the presence of two critical aggregation concentrations (CACs) for simple aliphatic chain amphiphiles, whereas a single CAC was obtained when glycine was introduced in the headgroup. Gel permeation chromatography studies indicate the presence of closed bilayer aggregates for all of the amphiphiles in aqueous solutions. XRD spectra indicate the presence of a non-interdigited bilayer structure. The presence of bilayer vesicles was confirmed by TEM measurements. Permeability of the bilayer membranes of the vesicles were investigated using the model water-soluble dye methylene blue. The vesicles obtained with nicotinic acid amphiphiles could be used as versatile carriers suitable for both hydrophobic and hydrophilic molecules.

Sodium Monododecylphosphate Vesicles Formed in Alcohol/Water Mixtures

“…A set of repeated peaks were clearly detected (Figure 3), which is the feature of lamellar structures. The d ‐spacing (corresponding to the thickness of the bilayer membrane [35] ) was estimated from the Bragg's equation to be ca . 3.81 nm.…”

Solvent Effects on Gelation Behavior of the Organogelator Based on L-Phenylalanine Dihydrazide Derivatives

“…Using the Kamlet–Taft model, the hydrogen-bonding effect of solvents was found to be more precisely related to the gelation ability [32,33]. The Kamlet–Taft parameters [34] (polarity parameter (π*), hydrogen-bonding donating capacity (α), and accepting capacity (β)) of some related solvents are shown in Table 2.…”

“…The structure of organogels was formed via hydrogen bonding and van der Waals forces [37], and the driving forces for gelation were evaluated by FTIR spectra [31,32,33]. The FTIR spectra of the xerogel, gel, and solution of compound 4 in CCl 4 are shown in Figure 4.…”

Effect of Amide Bonds on the Self‐Assembly of Two Synthesized Sulphonamido Group Based Amphiphiles: Application in Formation of Stable Silver Nanoparticles.

“…The nature of aggregates formed by the amphiphiles was studied by the XRD experiment according to the procedure described in our earlier publication . The X‐ray diffraction pattern of the cast film was recorded in the range 2θ=2° −12° and are depicted in SI.…”

“…The nature of aggregates formed by the amphiphiles was studied by the XRD experiment according to the procedure described in our earlier publication. [35] The X-ray diffraction pattern of the cast film was recorded in the range 2q = 28 À128 and are depicted in SI. The parameters such as peak position, corresponding planes and interplanar distance obtained from XRD study, as well as hydrophobic chain length l c , determined from optimized structure (obtained from the energy-minimized structure via the density functional theory by Gaussian 9.0) for the two amphiphiles are listed in Table 2.…”